NDROGEN-insensitivity syndromes in 46,XY fetuses result in various degrees of impairment in genital virilization. 1 These syndromes are caused by mutations in the androgen receptor gene that result in decreased binding of androgen to the receptor. [2][3][4][5][6][7][8][9] As a consequence, the transcriptional activity of the androgen-androgen-receptor complex is reduced, and therefore, genital virilization is reduced. The androgen receptor, like other steroid hormone receptors, has two major transactivation domains 10 -activation function 1 (AF-1) in the N-terminal region 11-13 and activation function 2 (AF-2) in the C-terminal ligand-binding domain 14 -that interact with the target genes directly as well as indirectly by means of intermediary coactivators. 15 We describe a patient in whom the complete androgen-insensitivity syndrome was diagnosed on the basis of phenotypic and endocrinologic findings, but who had no mutations in the androgen receptor gene. Detailed studies revealed that transmission of the activation signal from the AF-1 region of the androgen receptor was disrupted, suggesting that a coactivator interacting with the AF-1 region of the androgen receptor was lacking in this patient. CASE REPORTA 19-year-old woman reported primary amenorrhea. The patient had normal breast development and normal female external genitalia, but she had no pubic or axillary hair, and the vagina was short (6 cm in length) and ended in a blind pouch. Abdominal exploration revealed no uterus, but testes were present, which were resected. Histologic examination of the testes revealed small numbers of immature Sertoli cells and germ cells and a moderate num-A ber of Leydig cells. Preoperatively, the patient's serum testosterone concentration was 614 ng per deciliter (21.3 nmol per liter) and her serum 5 a -dihydrotestosterone concentration was 49 ng per deciliter (1.7 nmol per liter); both values were within the normal range for men. The karyotype was 46,XY. The patient was given a diagnosis of complete androgen-insensitivity syndrome. Her two older sisters were not affected. METHODS Analysis of the Androgen ReceptorThe study was approved by the local institutional review committee, and written or oral informed consent for a genital-skin biopsy was obtained from the patient, another patient with complete androgen-insensitivity syndrome, and five normal men. Primary culture of genital-skin fibroblasts, androgen-binding assays, and sequence analysis of the androgen receptor gene were performed as previously described. 4-9 Tissue concentrations of androgen receptor messenger RNA (mRNA) were determined by a quantitative reverse-transcriptase-polymerase-chain-reaction assay (RT-PCR) as described previously. 16,17 Plasmid Construction and Reporter AssayWe constructed a firefly-luciferase-reporter vector (pGL3-MMTV), which was under the control of the mouse-mammarytumor virus (MMTV) promoter, by inserting the mouse-mammary-tumor virus long terminal repeat promoter 18 into a pGL3 basic vector (Promega). The expression vectors for ...

Although evidence indicates that dehydroepiandrosterone (DHEA) exerts direct physiological effects, its mechanism of action remains unknown. DHEA binding sites were examined using a whole-cell binding assay in a human T lymphoid cell line, PEER, revealing that a single class of high-affinity binding sites for DHEA (dissociation constant = 7.4 +/- 0.53 nmol/L, mean +/- SE, n = 4) was greatly increased when treated with DHEA, phorbol-12-myristate-13-acetate, and the Ca2+ ionophore A23187. Bound [3H]DHEA was displaced sensitively by DHEA and secondarily by dihydrotestosterone, but not effectively by other steroids, including DHEA sulfate. These results not only indicate the existence of a DHEA receptor, but also suggest that T cells become susceptible to regulation by DHEA during the process of signal-induced activation.

Nur77 is a member of the steroid receptor superfamily and is known to be expressed in animals under stress. We studied the role of nur77 in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis during the stress response using a murine pituitary corticotrope cell line, AtT-20. Corticotropin-releasing hormone (CRH), a stress mediator in the HPA axis, induced the expression of nur77 transiently in AtT-20 cells. Gel shift assay showed that nur77 bound to negative glucocorticoid responsive element (nGRE) in the promoter of the human proopiomelanocortin (POMC) gene and the formation of the nur77-nGRE complex increased after treatment of the cells with CRH. Negative GRE is known to be necessary for the negative regulation by glucocorticoid of the POMC gene expression. In stable transformants of AtT-20 cells expressing a human homolog of nur77, NAK-1, at a high level, glucocorticoid-mediated inhibition of both POMC mRNA induction and ACTH secretion was significantly lower than that in the NAK-1-nonexpressing cells (P<0·001). These results strongly suggest that nur77 antagonizes the negative feedback effect of glucocorticoid on the synthesis and secretion of ACTH in pituitary corticotropes. This suggests that nur77 plays an important role in the pituitary gland in the biological adaptation to overcome stress.

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These results suggest strongly that decreased expression of GR alpha in pituitary adenomas may be the major reason for the marked insensitivity to the 8-mg dexamethasone suppression test observed in two patients with Cushing's disease.